Chelsea went down 1-0 in Yokohama and Piazon, an unused substitute in the match, hit out at an "unacceptable" lack of fight shown by Rafael Benitez's team.
Speaking to Brazilian website UOL Esporte, Piazon said: "A lot of us were missing the desire to be champion. I think Ramires and David Luiz, the Brazilians were the ones who gave the most, and now they are sad."
He went on: "We lacked character. Nobody wanted to fight...
"We went into a final without the will to win, and that's unacceptable."
Piazon added that Luiz was one of the few players to show any sign of disappointment after the match.
"David was upset," he said. "I'm not surprised. He was one of the few who cared and gave what he had in the match."
Source: PA
Source: PA